Childhood mood disorders represent a significant public health concern, with 6 to 11% of the population suffering from symptomology. Among those affected, 70% will have a recurrence during childhood and/or adolescence, and 50% will continue to experience symptoms in adulthood. These patterns of chronicity suggest that mental health problems observed later in life often have identifiable markers during early childhood. Therefore, early identification and intervention is critical. The NIH has put forth the Research Domain Criteria (RDoC), which acts as a heuristic to examine mechanisms of mental illness by suggesting the investigation of several behaviorally and biologically based processes. Although RDoC provides a valuable theoretical framework, the applicability of RDoC for developmental psychopathology research has been limited, primarily due to a lack of validated, feasible, standardized assessment batteries to examine RDoC domains in young children. Our aim is to create and validate behavioral and neurobiological assessments for young children in order to examine the relevance of RDoC domains, Positive and Negative Valence, for childhood depression and anxiety that often precedes or commingles with it. Specifically, we will study the constructs of reward valuation (Positive Valence) and acute threat (Negative Valence) using behavioral and neurophysiologic correlates of these constructs and test for associations with clinically assessed depression and anxiety in 4-6 year old children. Recruitment through the Infant and Early Childhood Clinic at the University of Michigan's Department of Psychiatry, as well as general pediatrics clinics in our health system, will ensure that a broad spectrum of anxiety and depressive symptoms, across the clinical to non-clinical range are represented in the children in our study. We seek NIH pilot funding to investigate the feasibility of behavioral and neurophysiology tasks that will long-term 1) inform assessment procedures, blending basic science advances with accessibility for patients and their families; 2) improve our characterization of underlying mechanisms of child anxiety and depression; and 3) inform subsequent interventions to address personalized child-level deficits. Findings will prove high impact as the NIMH considers the study and future application of RDoC criteria a high priority, and, yet, there are few empirical data exploring such application among young children. This proposal is responsive to the urgent need for validated, feasible, and standardized assessment batteries to examine RDoC domains in young children, and represents a critical step in a long-term plan to achieve effective and mechanism-based identification and treatment strategies for preschool-age children with depression and anxiety.